Zigzag Iterator.py

'''
Given two 1d vectors, implement an iterator to return their elements alternately.

Example:

Input:
v1 = [1,2]
v2 = [3,4,5,6] 

Output: [1,3,2,4,5,6]

Explanation: By calling next repeatedly until hasNext returns false, 
             the order of elements returned by next should be: [1,3,2,4,5,6].

Follow up: What if you are given k 1d vectors? How well can your code be extended to such cases?

Clarification for the follow up question:
The "Zigzag" order is not clearly defined and is ambiguous for k > 2 cases. If "Zigzag" does not look right to you, replace "Zigzag" with "Cyclic". For example:

Input:
[1,2,3]
[4,5,6,7]
[8,9]

Output: [1,4,8,2,5,9,3,6,7].


'''

class ZigzagIterator(object):

    def __init__(self, v1, v2):
        """
        Initialize your data structure here.
        :type v1: List[int]
        :type v2: List[int]
        """
        self.v = {0: v1, 1: v2}
        self.k = {0: -1, 1: -1}
        self.idx = len(self.v) - 1

    def next(self):
        """
        :rtype: int
        """
        return self.v[self.idx][self.k[self.idx]]

    def hasNext(self):
        """
        :rtype: bool
        """
        count = 0
        while True:
            self.idx = (self.idx + 1) % len(self.v)
            self.k[self.idx] += 1
            if self.k[self.idx] < len(self.v[self.idx]):
                return True
            else:
                count += 1
            if count == len(self.v):
                return False
        return False
            
        

# Your ZigzagIterator object will be instantiated and called as such:
# i, v = ZigzagIterator(v1, v2), []
# while i.hasNext(): v.append(i.next())